Johns-Hopkins University - Flesh-eating bacteria, than can only live inside the oxygen-free environment of tumor cells could be used in conjunctive with traditional chemotherapy to combat tumor cells, which are immune to normal drugs.

Flesh-eating bacteria, than can only live inside the oxygen-free environment of tumor cells could be used in conjunctive with traditional chemotherapy to combat tumor cells, which are immune to normal drugs.

Cancer researchers have traditionally been faced with a dilemma in combating tumors. While chemotherapy can be used to attack tumors, there comes a point when chemotherapy is rendered useless. This may be because the drugs used are ineffective at treating the necrotic regions of tumors.

Tumors normally supply themselves with nutrients and oxygen by growing blood vessels. However, some tumors' growth may be so rapid that their interiors become starved of blood and oxygen, becoming necrotic regions, composed of dead and dying cells.

While it may seem that these apparently weak regions should be easy to treat, in reality they are very difficult.

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Drugs can not reach this tissue due to the lack of blood supply and radiation treatments fail due the lack of oxygen. Once these treatments are stopped, surviving cells in the necrotic regions can once again begin to divide, wiping out any progress that was made.

However, a new approach combined with chemotherapy will allow scientists to "hit the tumor from both the inside and the outside," according to Bert Vogelstein of Johns Hopkins School of Medicine and primary researcher in this study.

By utilizing anaerobic bacteria which thrive in oxygen-poor regions (such as the necrotic regions of the tumor) Dr. Vogelstein's team has been able to achieve amazing results.

The notion that anaerobic bacteria could be used to attack the necrotic regions of a tumor without harming healthy regions is not a new idea to cancer researchers. However, until now all microbes tested proved unsuccessful.

Vogelstein's team widened the scope of the search, analyzing 26 strains of bacteria. The team struck gold when they injected Clostridium novyi, a soil bacteria, into their mice which had large colon tumors.

The bacteria spread through the tumor consuming both living as well as dead tissue. However, the bacteria perished closed to the edge of the tumor, leaving the job unfinished.

To augment the treatment researchers combined the bacteria with a form of chemotherapy known as COBALT (combination bacteriolytic therapy). Of the eight mice given this combination treatment, the tumors shrank dramatically or disappeared in seven of them, returning in only one.

"The tumor died so quickly, you could almost watch it," says Vogelstein.

The drawback: three of the eight mice died. However, researchers believe that this is because the tumors were destroyed too quickly and that the waste flooded the animals' circulation.

While toxins spread quickly in small animals, they should not be lethal it humans.